The role of silica in radiation induced grafting and crosslinking of silica/elastomers blends

• Published in: Polymer (Guilford) Vol. 53; no. 21; pp. 4579 - 4584
• Main Authors: Dondi, D., Buttafava, A., Zeffiro, A., Conzatti, L., Faucitano, A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 28-09-2012; Elsevier
• Subjects: Applied sciences; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Radiation crosslinking; Radiation grafting; Silica-rubber blends; Technology of polymers; Radiation grafting; Silica-rubber blends; Radiation crosslinking; SBR; Filled polymers; Experimental study; Silica; Chemical coupling; Polymer filler interaction; Side reaction; Gamma radiation; Radiochemical vulcanization; Butadiene polymer; Reaction mechanism; Radiochemical reaction; Interface reaction
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2012.08.015

When silica/polybutadiene and silica/styrene-butadiene are submitted to γ irradiation at 77 K a scavenging of the silica radiolytic species by absorbed vinyl units takes place at the surface with concomitant grafting and crosslinking of the polymers. Key intermediate in such reactions are SiO2-bonded radicals of structure SiO2–C•(CH3)CH(R)(R′). The role of silica is rationalized in terms of the following steps: a) absorption of the radiation energy in the bulk of the silica particles followed by exciton migration at the surface; b) reactions of excited groups (silanols) with absorbed vinyl units giving SiO2-bonded radicals; c) crosslinking of the polymers initiated by grafted radicals.
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